Chemical management of Rhynchospora cephalotes in Baixo Tocantins-PA

Abstract

Aggressive weeds, such as Rhynchospora cephalotes, are the main weeds in areas with perennial crops and degraded pastures in the Amazonian environment. Studies show that the association of phenoxyacetic acids with other classes of herbicides may be a viable alternative in the management of difficult to control plants. The objective of this study was to evaluate the post-emergence efficacy of 2,4-D herbicide, alone or in combination, in the control of Rhynchospora cephalotes. The experimental design was randomized blocks with 4 replications. Isolated doses of 2,4-D (502,5, 1,005 and 2,010 g e.a. ha^-1) were applied as treatments and these were associated with picloran (960 g e.a. ha^-1), triclopyr (960 g e.a. ha^-1) and glyphosate (1,110 g e.a. ha^-1), one more control without application. The best results at the end of the evaluations, 42 days after application, were obtained by the three treatments of the mixture between 2,4-D and glyphosate, which presented control averages of R. cephalotes, around 98%. The association between the herbicides 2,4-D and glyphosate, at any dose used in this experiment, proved to be effective in controlling R. cephalotes, when applied in post-emergence.